Many developing countries generate millions of tons of agricultural wastes and forest residues every year. Handling and transportation of these materials which is difficult due to their low bulk density can easily be address through briquette production. Briquette quality which is greatly influence by its bulk density, calorific value and resistance to humidity is very important when deciding the materials and the particle size that will produce briquette of good quality. This research work centers on the assessment of particle size and biomass type that will give good bulk density and resistance to humidity. Three type of biomass materials with various particle sizes were selected viz: maize stalk (0.6, 1.0, 2.36, 4.75, 8.0, 9.5 and12.5mm), rice husks (0.6, 1.0, and 2.36mm), and sawdust(0.6, 1.0, 2.36, 4.75, 8.0, 9.5 and12.5mm). The bulk density and resistance to humidity was determined and it was discovered that rice husks briquette with particle size 0.6mm and 3% starch content have the best bulk density while maize briquette with particle size 4.75mm and 9% starch content give the best result for resistance to humidity therefore, for the purpose of packaging and transportation rice husks briquettes of size 0.6mm and 3% starch is recommended while for resistance to humidity, 4.75mm, 9% starch content of maize stalk briquette is recommended.